Mercury[141] has also been recommended; but there is no fact more certainly ascertained than this, that mercury uniformly exasperates this disease, especially when it has proceeded the length of ulceration. In this case, the sores enlarge rapidly, become much more painful, and bleed frequently. It is worthy of observation, that those who are affected with cancer, have in general the mercurial action induced very easily and very speedily[142]; and the changes which take place on the ulcer are equally rapid. This circumstance, of mercury increasing the disease, in so marked a manner as it usually does, ought not only to make surgeons careful of exhibiting this remedy, upon slight suspicions of the sore being venereal[143], but may likewise be attended to as a step toward the discovery of a better mode of treatment for cancer than we yet possess; because if, at any time, we discover the means of directly displacing and counteracting the mercurial action, we may perhaps find the same to be useful in abating the cancerous; these two actions appearing to possess some general coincidence, from their mutual effect in increasing each other. [141] Alongst with this, it was customary to prescribe decoctions of guaiac, sarsaparilla, &c. [142] It likewise continues very long after giving up the use of the mercury. [143] Some cases of this kind I have already mentioned. Copper, in the form of cuprum vitriolatum, has been used in cancer; and one case is recorded, in which it is said to have produced a cure; but in every other case it has failed; and, from the violent effects which it is apt to produce, considerable danger attends its exhibition. Muriated barytes has been proposed as a cure for this disease; but now none employ it with this expectation. The same remedies which internally have been supposed to cure cancer, have also been proposed as local applications. Amongst the older practitioners, narcotics were very currently employed as a dressing for cancerous sores. Vesalius used cloths dipped in the juice of the solanum; whilst others employed it mixed with oil of roses, and preparations of lead and antimony. Others had recourse to the hyocyamus; whilst of late the cicuta poultices seem to have superseded the use of most other narcotic preparations. These have, undoubtedly, in many cases, abated the pain, and diminished the fœtor; but this is all which can reasonably be expected from them; and even this expectation will not always be realised.